SLUSBO6C JANUARY 2014 – October 2018 TPS40425
PRODUCTION DATA.
Format | N/A | ||||
Description | The WRITE_PROTECT command is used to control writing to the PMBus device. The intent of this command is to provide protection against accidental changes. This command is not intended to provide protection against deliberate or malicious changes to a device's configuration or operation. All supported commands may have their parameters read, regardless of the WRITE_PROTECT settings.
Note: Valid setting of WRITE_PROTECT[7:5] bits disables the RESTORE_USER_ALL command’s ability to restore EEPROM data to protected PMBus Control/Status Registers (CSRs). However, an EEPROM (via the RESTORE_USER_ALL execution) restores the data to any registers that remain unprotected (either by a valid WRITE_PROTECT[7:5] setting, or by any invalid setting of these bits ). No WRITE_PROTECT[7:5] bit setting affects the Reset-Restore operation. All registers having EEPROM support get updated. Likewise, STORE_USER_ALL command operation remains unaffected. |
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Default | 000XXXXX (binary)
The default power-up state can be changed using the STORE_USER_ALL command. |
r/wE | r/wE | r/wE | |||||
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
bit7 | bit6 | bit5 | X | X | X | X | X |
Bits | Field Name | Description |
---|---|---|
7 | bit7 | (Format: binary)
0: (Default) See table below. 1: Disable all writes except for the WRITE_PROTECT command. (bit5 and bit6 must be 0 to be valid data) |
6 | bit6 | (Format: binary)
0: (Default) See table below. 1: Disable all writes except for the WRITE_PROTECT, OPERATION, and PAGE commands. (bit5 and bit7 must be 0 to be valid data) |
5 | bit5 | (Format: binary)
0: (Default) See table below. 1: Disable all writes except for the WRITE_PROTECT, OPERATION, PAGE, and ON_OFF_CONFIG commands. (bit6 and bit7 must be 0 to be valid data) |
4:0 | X | X indicates writes are ignored and reads are 0.
Note: Any values written to read-only registers are ignored. |
Invalid data written to WRITE_PROTECT[7:5] causes the ’cml’ bit in the STATUS_BYTE and the ‘ivd’ bit in the STATUS_CML registers to be set. INVALID DATA ALSO RESULTS IN NO WRITE PROTECTION (WRITE_PROTECT = 00h)! |
Data Byte Value | Action |
---|---|
1000 0000 | Disables all WRITES except to the WRITE_PROTECT command. |
0100 0000 | Disables all WRITES except to the WRITE_PROTECT, OPERATION, and PAGE commands. |
0010 0000 | Disables all WRITES except to the WRITE_PROTECT, OPERATION, PAGE, and ON_OFF_CONFIG commands. |